1) Field
Embodiments of the present invention relate to methods of forming hetero-layers with reduced surface roughness and bulk defect density on non-native surfaces and the structures formed thereby.
2) Description of Related Art
The fabrication of next-generation semiconductor devices involves forming transistor devices over heterogeneous semiconductor layers on non-native substrates having a different lattice constant. The integration of such heterogeneous semiconductors layers on non-native substrates is typically achieved by using buffers layers to provide a means of gradually changing the lattice constant from that of the substrate to that of the active device layer. Defects are generated during the formation of buffer layers and result in high bulk defect densities as well as rough surfaces/interfaces. Annealing the buffer layers may reduce bulk defect densities, however, it also typically increases the surface roughness. For subsequent successful device integration and performance, it is necessary to reduce both bulk defect density and surface roughness. The conventional “growth-anneal-growth anneal” approach that alternates between growing and annealing buffer layers does not provide a means to form buffer layers having bulk defect densities and surface roughness that are sufficiently low to successfully manufacture next-generation high-k metal gate transistor devices.